Transmitting apparatus, transmission method and signal generating apparatus

Abstract

A transmitting apparatus and method transmits different modulated signals from a plurality of antennas, and employs a configuration that includes a modulation section that obtains a modulated signal by performing signal point mapping of transmit bits using a signal point arrangement that is divided into a plurality of signal point sets on the IQ plane, whereby the minimum distance between signal points within a signal point set is smaller than the minimum signal point distance between signal point sets; and an antenna that transmits a modulated signal obtained by the modulation section. A signal point generating apparatus generates a first and second symbols to be transmitted by first and second antennas, respectively.

1. A transmitting apparatus comprising:
 a first symbol generation section that selects one point of a plurality of first signal points as a first symbol, the plurality of first signal points being arranged on an IQ plane based on a first mapping pattern; 
 a second symbol generation section that selects one point of a plurality of second signal points as a second symbol, the plurality of second signal points being arranged on the IQ plane based on a second mapping pattern; 
 a first antenna that transmits the first symbol; and 
 a second antenna that transmits the second symbol in a common frequency band and common transmission time with the first symbol, wherein: 
 a plurality of bits are allocated to each of the plurality of first signal points; 
 a first bit set in the plurality of bits is allocated to a first position on the IQ plane; 
 the plurality of first signal points are divided into four groups based on specific two bits in the plurality of bits; 
 in each of the groups, the plurality of first signal points are arranged per first distance in a horizontal direction or in a vertical direction; 
 a minimum distance between signal points in one of the four groups and signal points in a rest of the groups is a second distance which differs from the first distance; 
 the plurality of bits are allocated to each of the plurality of second signal points; 
 the first bit set in the plurality of bits is allocated to a second position on the IQ plane; and 
 the second position and the first position are different. 
 
     
     
       2. The transmitting apparatus according to  claim 1 , wherein:
 a number of the plurality of first signal points is sixteen or sixty-four; and 
 a number of the plurality of second signal points is sixteen or sixty-four. 
 
     
     
       3. The transmitting apparatus according to  claim 1 , further comprising an encoding section that collectively encodes transmission bits mapped on a specific signal point in the first mapping pattern. 
     
     
       4. The transmitting apparatus according to  claim 3 , wherein the encoding section encodes the transmission bits mapped on the specific signal point in the first mapping pattern, with higher error correction capability than other transmission bits. 
     
     
       5. A signal generating apparatus that generates a first symbol to be transmitted by a first antenna and a second symbol to be transmitted by a second antenna in a common frequency band and common transmission time, the apparatus comprising:
 a first symbol generation section that outputs one point of a plurality of first signal points to the first antenna as a first symbol, the plurality of first signal points being arranged on an IQ plane based on a first mapping pattern; and 
 a second symbol generation section that outputs one point of a plurality of second signal points to the second antenna as a second symbol, the plurality of second signal points being arranged on an IQ plane based on a second mapping pattern, wherein: 
 a plurality of bits are allocated to each of the plurality of first signal points; 
 a first bit set in the plurality of bits is allocated to a first position on the IQ plane; 
 the plurality in first signal points are divided into four groups based on specific two bits of the plurality of bits; 
 in each of the groups, the plurality of first signal points are arranged per first distance in a horizontal direction or in a vertical direction; 
 a minimum distance between signal points in one of the four groups and signal points in a rest of the groups is a second distance which differs from the first distance; 
 the plurality of bits are allocated to each of the plurality of second signal points; 
 the first bit set in the plurality of bits is allocated to a second position on the IQ plane; and 
 the second position and the first position are different. 
 
     
     
       6. The signal generating apparatus according to  claim 5 , wherein:
 a number of the plurality of first signal points is sixteen or sixty-four; and 
 a number of the plurality of second signal points is sixteen or sixty-four. 
 
     
     
       7. The signal generating apparatus according to  claim 5 , further comprising an encoding section that collectively encodes transmission bits mapped on a specific signal point in the first mapping pattern. 
     
     
       8. The signal generating apparatus according to  claim 7 , wherein the encoding section encodes the transmission bits mapped on the specific signal point in the first mapping pattern, with higher error correction capability than other transmission bits. 
     
     
       9. A transmission method comprising:
 a first symbol generation step of selecting one point of a plurality of first signal points as a first symbol, the plurality of first signal points being arranged on an IQ plane based on a first mapping pattern; 
 a second symbol generation step of selecting one point of a plurality of second signal points as a second symbol, the plurality of second signal points being arranged on the IQ plane based on a second mapping pattern; and 
 a transmission step in which a first antenna transmits the first symbol and a second antenna transmits the second symbol in a common frequency band and common transmission time with the first symbol, wherein: 
 a plurality of bits are allocated to each of the plurality of first signal points; 
 a first bit set in the plurality of bits is allocated to a first position on the IQ plane; 
 the plurality of first signal points are divided into four groups based on specific two bits of the plurality of bits; 
 in each of the groups, the plurality of first signal points are arranged per first distance in a horizontal direction or in a vertical direction; 
 a minimum distance between signal points in one of the four groups and signal points in a rest of the groups is a second distance which differs from the first distance; 
 the plurality of bits are allocated to each of the plurality of second signal points; 
 the first bit set in the plurality of bits is allocated to a second position on the IQ plane; 
 the second position and the first position are different. 
 
     
     
       10. The transmission method according to  claim 9 , wherein:
 a number of the plurality of first signal points is sixteen or sixty-four; and 
 a number of the plurality of second signal points is sixteen or sixty-four. 
 
     
     
       11. The transmission method according to  claim 9 , further comprising an encoding step of collectively encoding transmission bits mapped on a specific signal point in the first mapping pattern. 
     
     
       12. The transmission method according to  claim 11 , wherein the encoding step encodes the transmission bits mapped on the specific signal point in the first mapping pattern, with higher error correction capability than other transmission bits.